Volatile organic compounds in preen oil and feathers - a review

During the breeding season, lymphocytes assemble into ellipse-shaped clusters in the uropygial gland of the jungle crow Corvus macrorhynchos

BACKGROUND

Recent studies indicate that the uropygial gland produces intraspecific chemosensory cues. The jungle crow Corvus macrorhynchos, which is a type of passerine, exhibits extreme morphological variation in the gonadal gland during the breeding season. Because the uropygial gland of the jungle crow sometimes exhibits morphological changes during the breeding season, we attempted to clarify the morphological changes in the uropygial gland of the jungle crow according to development and season.

METHODS

Captured birds were divided into three age groups according to the color of their upper palate: <1 year, 1-2 years, and >2 years old. Paraffin sections of the uropygial gland were stained with hematoxylin and eosin, Elastica van Gieson, Giemsa, and a proliferating cell nuclear antigen antibody.

RESULTS

Sexual dimorphism was not seen in the morphology of the uropygial gland in the jungle crow. However, changes due to growth and season were identified. During the breeding season in birds>2 years old, lymphocytes formed ellipse-shaped clusters around the glandular cavity. These clusters were invaded by collagen fibers from spherical cells.

CONCLUSIONS

Collagen fibers, which develop from spherical cells, seem to be related to lymphoid cluster migration. Ellipse-shaped lymphoid clusters may play a crucial role in reproductive behavior during the breeding season.

Blood Kinetics of Lipophilic and Proteinophilic Pollutants during Two Types of Long-Term Fast in King Penguins

In vertebrates, fasting is an intricate physiological process associated with strong metabolic changes, yet its effect on pollutant residue variation is poorly understood. Here, we quantified long-term changes in plasma concentrations of 20 organochlorine and 16 perfluoroalkyl pollutants in king penguins Aptenodytes patagonicus during the breeding and molting fasts, which are marked by low and high levels of protein catabolism, respectively, and by strong lipid use. The profile of measured pollutants in plasma was dominated by perfluorooctanesulfonic acid (PFOS, initial relative contribution of 60%). Initial total pollutant concentrations were similar in molting (3.3-5.7 ng g-1 ww) and breeding penguins (range of 4.2-7.3 ng g-1 wet weight, ww). Long-term fasting (25 days) for molting and breeding led, respectively, to a 1.8- and 2.2-fold increase in total plasma pollutant concentrations, although the rate and direction of change were compound-specific. Hexachlorbenzene (HCB) and PFOS concentrations increased in plasma (net mobilization) during both types of fasting, likely due to lipid use. Plasma perfluoroundecanoate (PFUnDA) and perfluorotridecanoate (PFTrDA) concentrations increased in breeders (net mobilization) but decreased in molting individuals (net excretion), suggesting a significant incorporation of these pollutants into feathers. This study is a key contribution to our understanding of pollutant variation in blood during long-term fasting in wildlife.